使用自定义的Activity栈来管理android的Activity

由于Android未提供相应的多个activity管理的功能,只能在一个Activity的对象里面调用finish来关闭自己,不能关闭其他的Activity。

比如我们想实现一个功能从屏幕A—>屏幕B—>屏幕C—>屏幕D,然后在在转到屏幕D之前将屏幕B和C关闭,在屏幕B和屏幕C界面点击会退按钮都可以回退到上一个屏幕,但是在屏幕D上点击会退按钮让其回退到A。

此外在一些循环跳转的界面上如果不在合适的地方将一些不需要的屏幕关闭,那么经过多次跳转后回导致内存溢出。对此我们可以设计一个全局的Activity栈,使用这个栈来管理Activity。管理Activity的类的定义如下：

import java.util.Stack;import android.app.Activity;public class ScreenManager{private static Stack<Activity> activityStack;private static ScreenManager instance;private ScreenManager(){}public static ScreenManager getScreenManager(){if (instance == null){instance = new ScreenManager();}return instance;}public void popActivity(){Activity activity = activityStack.lastElement();if (activity != null){activity.finish();activity = null;}}public void popActivity(Activity activity){if (activity != null){activity.finish();activityStack.remove(activity);activity = null;}}public Activity currentActivity(){Activity activity = activityStack.lastElement();return activity;}public void pushActivity(Activity activity){if (activityStack == null){activityStack = new Stack<Activity>();}activityStack.add(activity);}public void popAllActivityExceptOne(Class cls){while (true){Activity activity = currentActivity();if (activity == null){break;}if (activity.getClass().equals(cls)){break;}popActivity(activity);}}}